1. Field of the Invention
The present invention relates to a laser annealing method for condensing laser beams by a microlens array to anneal only a thin-film transistor forming area of an amorphous silicon film. In particular, the present invention relates to a laser annealing method and a laser annealing apparatus for enhancing the irradiation position accuracy of laser beams by moving the microlens array following the movement of a substrate to be conveyed.
2. Description of Related Art
In a conventional laser annealing method, a plurality of laser beams is formed by a microlens array, and a focal point is formed for each beam, and each focal point of the beam is transferred to and imaged on an amorphous silicon film surface side, and laser processing is performed by irradiating the beams onto the amorphous silicon film surface, thereby recrystallization the amorphous silicon film in the thin-film transistor (hereinafter, referred to as “TFT”) forming area (for example, refer to Japanese Laid-open Patent Publication No. 2004-311906).
However, in such a conventional laser annealing method, laser beams are focused by the microlens array and only the amorphous silicon film in a plurality of TFT forming areas is annealed, and hence, there is an advantage in that the use efficiency of the laser beams increases. However, there is no disclosure about; moving the microlens array following the movement of a substrate to be conveyed while meandering, positioning each lens in the microlens array at each TFT forming area, and irradiating the laser beams. Consequently, at the time of conveying and annealing a large substrate having a size of one meter or more on one side, when the substrate is conveyed while meandering, it can be difficult to anneal only each TFT forming area reliably due to the mechanical accuracy of a conveying mechanism.